As a related art, a socket for a semiconductor package having a plurality of solder balls arranged in a grid shape as shown in FIG. 13 is available. This experimental evaluation package socket 300 has a plurality of contacts 301 arranged in a grid shape to correspond to the arrangement of solder balls S of a semiconductor package 350, a socket main body 302 equipped with each of the contacts 301, and a placing plate 303 on which the semiconductor package 350 is placed. First and second contact pieces 304 and 305 are provided to the leading end of each contact 301 to be contactable with the solder ball S while clamping the same from the both sides.
The semiconductor package 350 is inserted through an opening into the socket 300 of the above construction so that the solder balls 350 are respectively disposed between the first contact pieces 304 and the second contact pieces 305, and a slider 306 is moved upwardly in the drawing, thereby abutting slope portions 306a and 306b provided to the slider 306 against slope portions 304a and 305a of the first and second contact pieces 304 and 305. This causes the first and second contact pieces 304 and 305 to be displaced to be close to each other, thereby contacting and clamping the solder balls S from both sides.
In the socket 300 of the above construction, the leading ends of the first and second contact pieces 304 and 305 extends above the upper surface (the placing surface) of the placing plate 303, and therefore when the semiconductor package 350 is inserted, the solder ball S may be caught by the first and second contact pieces 304 and 305 or the like, resulting in difficulty in disposing the solder ball S between the first contact piece 304 and the second contact piece. This problem frequently occurs particularly in case of being an IC package in which the solder balls are arranged in a narrow pitch and full grid.
The aforementioned problem can be solved by accurately mating the solder balls S to the first and second contact pieces 304 and 305 when the package socket 350 is inserted, but this accurate mating requires the time-consuming work, causing another problem, i.e. a difficulty in conducting an experiment and evaluation for the semiconductor package in a speedy fashion.